docs: def _setbin_unsafe(self, binstring):
          """Same as _setbin_safe, but input isn't sanity checked. binstring mustn't start with '0b'."""
          length = len(binstring)
          # pad with zeros up to byte boundary if needed
          boundary = ((length + 7) // 8) * 8
          padded_binstring = binstring + '0' * (boundary - length)\
                             if len(binstring) < boundary else binstring
          try:
              bytelist = [int(padded_binstring[x:x + 8], 2)
                          for x in xrange(0, len(padded_binstring), 8)]
          except ValueError:
              raise CreationError("Invalid character in bin initialiser {0}.", binstring)
          self._setbytes_unsafe(bytearray(bytelist), length, 0)